The =œsophagus= is relatively wide and dilatable except at its origin.
The constriction at its origin is termed the =isthmus œsophagi=. The
cardiac end is slightly dilated; it joins the stomach under the tenth or
eleventh thoracic vertebra, slightly to the left of the median plane.
The muscular tissue is striated and consists mainly of two layers of
spiral fibers which cross each other; near the cardia, however, the
fibers are longitudinal and circular. There are mucous glands and lymph
glands in the submucosa throughout.
[Illustration: